Adjustable crusher

ABSTRACT

The application presents an adjustable cone crusher which has a hydraulic cylinder-plunger-combination (15, 4) for adjusting the setting and supporting a main shaft at its bottom end. The combination contains a bypass channel (21), through which the pressure medium escapes from the cylinder when the combination has been extended by a certain distance. In this way the crushing cone is prevented from rising too much upwards.

FIELD OF ART

The invention relates to hydraulically adjustable cone crushers orgyratory crushers. Specifically, the invention concerns a safety deviceto prevent the main shaft from being raised too high when adjusting thesetting.

PRIOR ART

A cone crusher has a vertical eccentric shaft provided with an obliqueinterior hole. The hole mounts a main shaft to which a crushing cone isattached. The crushing cone is surrounded laterally by a crusher body. Acrushing chamber is formed by an inner crushing blade attached to thecrushing cone and by an outer crushing blade attached to the body. Whenthe eccentric shaft is rotated, the main shaft and thus also thecrushing cone are made to move oscillatingly, whereby the gap betweenthe crushing blades will vary at each point during the cycle. Thesmallest gap occurring during a cycle is called the crusher setting.

The crusher setting is often made adjustable with the aid of a hydraulicsystem, so that the main shaft can be moved in a vertical direction inrelation to the body.

The main shaft is often supported on the body at its top end by using asupporting top bearing. A gyratory crusher generally just means thissubordinated kind of cone crusher.

As the crushing blades wear down, the main shaft must be raisedcorrespondingly in order to achieve the same setting. With gyratorycrushers in particular there is then a risk of driving the crushing coneinto the bearing housing of the supporting top bearing and of thusdamaging the crusher. To prevent this, such various limit switches andindicators have been used in crushers of the prior art as usuallyoperate electrically. However, a problem with these has been theirunreliable operation.

DESCRIPTION OF THE INVENTION GENERAL DESCRIPTION

An essential feature of the invention is a bypass channel through whicha pressure medium escapes from the cylinder for adjusting the settingupon exhaustion of the adjustment margin. In this way the main shaftcannot be driven too high.

DESCRIPTION OF THE DRAWINGS

The appended drawings are an integrated part of the description of theinvention.

FIG. 1 shows a gyratory crusher in accordance with the invention.

FIG. 2 shows en enlarged detail of the crusher shown in FIG. 1.

FIG. 3 shows the adjustment cylinder and the lower part of the mainshaft in another gyratory crusher in accordance with the invention.

FIG. 4 shows the adjustment cylinder and the main shaft in a thirdgyratory crusher in accordance with the invention.

FIG. 5 shows a detail of the crusher shown in FIG. 4.

DETAILED DESCRIPTION

The invention can be applied to all types of cone crushers provided withhydraulic equipment for adjusting the setting. The invention isespecially suitable for gyratory crushers equipped with a supporting topbearing and wherein the setting is adjusted by moving the main shaft inrelation to the eccentric shaft.

The adjusting plunger is preferably a plunger surrounding the eccentricshaft and with the main shaft pressing against its bottom. In this way acompact structure is obtained, wherein the bypass channel for pressuremedium in accordance with the invention can also be convenientlyarranged by conducting pressure medium between the cylinder and theplunger into the crusher's lubricating oil circuit.

However, the invention is also suitable for traditional crushers whichhave a conventional adjusting cylinder and a piston located entirelybelow the main shaft.

In the solution in accordance with the invention the pressure medium isallowed to flow away from the cylinder to a lower pressure by way of aspecial bypass channel, when the main shaft reaches its topmostpermissible position. The quantity of pressure medium can then no longerbe increased in the cylinder and thus the main shaft can not be raisedfurther.

The bypass channel for pressure medium may run between the cylinder andthe plunger, through the cylinder or through the plunger. The bypasschannel may consist, for example, of one or several grooves, holes orchamfers made in the cylinder wall. The medium may flow from thecylinder into the crusher's lubricant circuit or into the hydraulicadjusting circuit or it may leave the system altogether.

The safety device in accordance with the invention is first of allreliable. Normally it is also inherently such that it cannot be madenon-operative even intentionally and thus to try to drive the main shaftall the way to the risk limit.

Certain advantageous applications of the invention are described in thefollowing in greater detail and referring to the appended drawings ofthe specification.

EXAMPLE 1

The main components of the crusher in FIG. 1 are a body 1, whichcontains a main shaft 2, an eccentric shaft 3, an adjusting plunger 4and a driving shaft 5.

Main shaft 2 mounts a cone 6 mounting a conical inner crushing blade 7.A nut 8 fitted with a thread to the main shaft functions as the meansfor mounting the inner crushing blade.

The top end of main shaft 2 is journalled in body 1 with the aid of asupporting top bearing 9, which allows the main shaft to perform aswinging pendulous motion and a motion in a vertical direction inrelation to the body. The bottom end of the main shaft rests onadjusting plunger 4 through a thrust bearing combination 10 allowing themain shaft end to perform a circular motion.

Body 1 has a detachable top part to which are mounted an outer crushingblade 11 and an inner crushing blade 7 which constitute a crushingchamber. The crushing blades are wearing parts which are exchangeable.

Eccentric shaft 3 has a cylindrical inner hole into which main shaft 2is fitted with the aid of an oblique eccentric bearing 12. The eccentricshaft mounts around it a secondary gear 13 meshing with a primary gear14 on driving shaft 5. The rotational motion of the driving shaft isthus turned into a forced rotation of the eccentric shaft and theeccentric bearing around a vertical axis, which for its part bringsabout an oscillating motion of the main shaft.

Adjusting plunger 4 is a plunger surrounding eccentric shaft 3 andhaving main shaft 2 pressing against its bottom. The adjusting plungeris sealed into a cylinder 15 in body 1. The cylinder extends above thebottom end of the eccentric shaft so that radial forces of the mainshaft can be transferred into the body through the plunger and thecylinder.

Cylinder 15 is combined with a hydraulic circuit. By changing thequantity of pressure medium 16 in the cylinder it is possible to raiseand lower plunger 4 and thus also main shaft 2 and in this way to adjustthe setting, that is, the gap between crushing blades 7 and 11. As thecrushing blades wear, the main shaft must be raised correspondinglyupward for keeping up a certain setting.

The bearings and gears of the crusher are lubricated by circulatinglubricant through them. The same liquid (oil) functions both as pressuremedium 16 and as lubricant, whereby the liquid is pumped from the samecontainer in either circuit. The lubricant is removed from an assembly17. The pressure medium is brought into cylinder 15 from an assembly 18.

Plunger 4 is sealed into cylinder 15 with the aid of a cylinder bushing19 and an annular seal 20.

To prevent main shaft 2 from being raised so high that nut 8 wouldcontact the bearing housing of supporting top bearing 9, cylinderbushing 19 and cylinder 15 are provided with a groove 21 (FIG. 2)functioning as a bypass channel. As seal 20 rises to the level of thegroove, pressure medium 16 is allowed to flow from cylinder 15 throughthe groove into the lubricating oil circuit, where there is practicallyno counterpressure at all. The vertical distance H between the bypasschannel and the plunger seal 20 is dimensioned so that it corresponds toa safe raising margin for the main shaft.

In addition, the system may be used for assessing the degree of wear ofbearing combination 10 when main shaft 2 is driven to its top positionand the distance between nut 8 and supporting top bearing 9 is measured.

EXAMPLE 2

FIG. 3 shows the same type of gyratory crusher as FIGS. 1 and 2 providedwith a movable adjusting plunger 4. In the wall of this adjustingplunger there is a hole 22 extending from the top all the way to thecylinder chamber and having a back-pressure valve 23 at its bottom end.In a normal situation the valve will prevent pressure medium 16 fromescaping from the cylinder chamber through the hole. The hole also has arod 24 with a top end extending above the top edge of the plunger andwith its bottom end against a closing means in the valve. When theplunger rises so high that the top end of the rod contacts the lowersurface of an annular flange 25 at the top end of eccentric shaft, thebottom end of the rod will press the closing means of the valvedownwards, so that the valve will open and the pressure medium will thusbe free to escape through the hole. In this way, the adjusting plungerand the main shaft can not be raised further upwards. When the adjustingplunger is lowered, the valve will close and will again operatenormally. The rod is dimensioned so that the valve will open just beforethe crushing cone contacts the bearing housing of the supporting topbearing as the main shaft is being raised.

EXAMPLE 3

FIGS. 4 and 5 show such a traditional adjustment solution, wherein thecylinder 15.1 has a movable adjusting piston 4.1 located entirely belowthe main shaft 2 and the eccentric shaft 3. In crushers of this typethere is usually a vertical groove 26 in one side of the adjustingpiston to receive a limiting pin 27 extending through the cylinder wall.The pin prevents the piston from rotating, but permits its verticalmotion.

In the solution in accordance with the invention a hole 22.1 is madefrom the bottom of groove 26 into the cylinder chamber with a valve 23.1located on its bottom. The hole contains a guiding pin 24.1 for theclosing means of the valve with its top end extending above the hole. Inaddition, a bypass channel 28 extends from the hole into a lubricantchamber 29 in piston 4.1. When the piston is raised so high that theguiding pin strikes against limit pin 27 for the rotational motion, theguiding pin will open the closing means of the piston and pressuremedium will flow from the cylinder by way of the bypass channel into thelubricant circuit in the piston.

We claim:
 1. An adjustable cone crusher, comprising:a body; an eccentricshaft positioned in the body and rotatable about a vertical axis, theeccentric shaft having a vertically oriented oblique hole; a main shaftjournalled in the hole of the eccentric shaft, the main shaft having abottom end and a top end; a hydraulic cylinder-plunger-combination, thehydraulic cylinder being adapted to receive a pressure medium tovertically extend the hydraulic cylinder-plunger-combination, the bottomend of the main shaft being supported on the hydrauliccylinder-plunger-combination so that extension of the hydrauliccylinder-plunger-combination causes upward movement of the main shaft,the hydraulic cylinder-plunger-combination including a bypass channelwhich is opened and closed depending upon the position of the plunger,said bypass channel being covered by the plunger so as to be closed whenthe plunger is located below a predetermined raised position and beingopen when the plunger is at the predetermined raised position to permitpressure medium in the cylinder to escape.
 2. The adjustable conecrusher as defined in claim 1, wherein the top end of the main shaft issupported on the body by a supporting top bearing.
 3. The adjustablecone crusher as defined in claim 1, wherein the plunger of the hydrauliccylinder-plunger-combination supports the main shaft.
 4. The adjustablecone crusher as defined in claim 3, wherein the plunger surrounds theeccentric shaft and includes a bottom supporting the main shaft.
 5. Theadjustable cone crusher as defined in claim 1, wherein the bypasschannel leads from the cylinder through a lubricant circuit and isadapted to be connected to a hydraulic circuit.
 6. The adjustable conecrusher as defined in claim 1, wherein a portion of the bypass channelis located between the hydraulic cylinder and the plunger.
 7. Theadjustable cone crusher as defined in claim 1, wherein the bypasschannel is located in the cylinder.
 8. An adjustable cone crusher,comprising:a body; an eccentric shaft positioned in the body androtatable about a vertical axis, the eccentric shaft having a verticallyoriented oblique hole; a main shaft journalled in the hole of theeccentric shaft, the main shaft having a bottom end and a top end; ahydraulic cylinder-plunger-combination, the hydraulic cylinder beingadapted to receive a pressure medium to vertically extend the hydrauliccylinder-plunger-combination, the bottom end of the main shaft beingsupported on the hydraulic cylinder-plunger-combination so thatextension of the hydraulic cylinder-plunger-combination causes upwardmovement of the main shaft, the hydraulic cylinder-plunger-combinationbeing provided with a bypass channel and a valve positioned in thebypass channel; an opening member adapted to open the valve, the openingmember being operatively associated with the plunger for moving with theplunger as the plunger moves between a predetermined raised position andpositions below the predetermined raised position, the opening memberengaging a counter surface when the plunger is in the predeterminedraised position to thereby open the valve to permit pressure medium inthe cylinder to escape.
 9. The adjustable cone crusher as defined inclaim 8, wherein the top end of the main shaft is supported on the bodyby a supporting top bearing.
 10. The adjustable cone crusher as definedin claim 8, wherein the plunger of the cylinder-plunger-combinationsupports the main shaft.
 11. The adjustable cone crusher as defined inclaim 8, wherein the plunger surrounds the eccentric shaft and includesa bottom supporting the main shaft.
 12. The adjustable cone crusher asdefined in claim 8, wherein the bypass channel is in the plunger. 13.The adjustable cone crusher as defined in claim 8, wherein the openingmember is an elongated rod.
 14. The adjustable cone crusher as definedin claim 8, wherein the opening member is a guiding pin.
 15. Thecombination of a safety device and an adjustable cone crusher, the conecrusher including a hydraulic cylinder-plunger-combination whichsupports a main shaft and a pressure medium space in the hydrauliccylinder for receiving a pressure medium to raise the main shaftvertically upwards through upward vertical movement of the plunger, thesafety device including a bypass channel in the hydrauliccylinder-plunger-combination which alternatively communicates with thepressure medium space and is prevented from communicating with thepressure medium space based on the position of the plunger, with thebypass channel being prevented from communicating with the pressuremedium space when the plunger is positioned below a predetermined raisedposition and being in communication with the pressure medium space whenthe plunger is in the predetermined raised position to permit pressuremedium in the pressure medium space to escape out of the pressure mediumspace.
 16. The combination of claim 15, wherein the bypass channel islocated in the cylinder.
 17. The combination of claim 15, wherein thetop end of the main shaft is supported in a supporting top bearing. 18.The combination of claim 15, wherein the bypass channel is located inthe plunger.